Re: [RFC] PCI extended conf space when MMCONFIG disabled because of e820

[Barry Scott <barry.scott@onelan.co.uk>]

Arjan van de Ven wrote:
> Chuck Ebbert wrote:
>> In-Reply-To: <p73ac8fqjix.fsf@verdi.suse.de>
>>
>> On 15 Jun 2006 03:45:10 +0200, Andi Kleen wrote:
>>
>>> Anyways I would say that if the BIOS can't get MCFG right then it's 
>>> likely not been validated on that board and shouldn't be used.
>>
>> According to Petr Vandrovec:
>>
>>  ... "What is important (and checked) is address of MMCONFIG reported 
>> by MCFG
>>  table...  Unfortunately code does not bother with printing that 
>> address :-(
>>  
>>  "Another problem is that code has hardcoded that MMCONFIG area is 
>> 256MB large.  Unfortunately for the code PCI specification allows any 
>> power of two between 2MB  and 256MB if vendor knows that such amount 
>> of busses (from 2 to 128) will be  sufficient for system.  With 
>> notebook it is quite possible that not full 8 bits  are implemented 
>> for MMCONFIG bus number."
>>
>>
>> So here is a patch.  Unfortunately my system still fails the test 
>> because
>> it doesn't reserve any part of the MMCONFIG area, but this may fix 
>> others.
>>
>> Booted on x86_64, only compiled on i386.  x86_64 still remaps the max 
>> area
>> (256MB) even though only 2MB is checked... but 2.6.16 had no check at 
>> all
>> so it is still better.
>>
>>
>> PCI: reduce size of x86 MMCONFIG reserved area check
>>
>> 1.  Print the address of the MMCONFIG area when the test for that area
>>     being reserved fails.
>>
>> 2.  Only check if the first 2MB is reserved, as that is the minimum.
>>
>> Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com>
>
> Acked-by: Arjan van de Ven <arjan@linux.intel.com>
>
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I have a system that fails to boot reporting MCFG problems.
I've applied your patch and it allowed the HP dc7600U to boot past
the MCFG problem. (I still have LVM problems - but that nothing
to do with this patch).

My shuttle P4 system also boots with your patch applied.

Barry